The connection of a saddle to a bicycle frame traditionally takes place using a seat post which carries, at one of its extremities, means for the attachment of the saddle, whereas its opposite extremity is inserted into the seat tube of the bicycle frame. A clamping ring is then utilized in order to retain the seat post in a determined longitudinal position in relation to the seat tube after its insertion and in this way to adjust the height of the saddle.
More recently, solutions have been proposed in order to integrate the seat posts as far as possible with the frame of the bicycle. One of these solutions, as described in particular in document CN201494543U, involves utilizing an intermediate component carrying the saddle and capable of being attached to the outside of the seat tube in the manner of a cap. With this solution, the frame must necessarily be provided with a long seat tube in order for it to be suitable a priori for a maximum number of cyclists. Thus, in order to adjust the height of the saddle, the only solution involves cutting the seat tube of the frame to the desired height.
Another known solution involves creating a system for attaching the saddle directly to the frame, the seat tube serving as a seat post. Here, the frame equipped with the attachment system must be made in a factory and customized for each individual cyclist.
According to another solution, as described in particular in document EP 1 877 299 B1 in the name of the applicant, the seat post is inserted into the seat tube, and an annular shoulder that is provided, either on the internal periphery of the seat tube, or on the external periphery of the seat post, permits the insertion of the seat post for a predetermined length.
All of the preceding solutions that are intended to integrate the seat post offer a certain aesthetic advantage and likewise improve the aerodynamics of the bicycle compared with a traditional seat post.
Nevertheless, adjustment of the height of the saddle when it is adapted to the height of the cyclist can only take place by cutting the seat tube. If the seat tube is cut too short, there is no way of turning back other than by changing the frame in its entirety.
Furthermore, if the owner of the bicycle wishes to sell it second-hand, he will be obliged to find a purchaser of the same height, or possibly shorter. This can constitute a disincentive to purchase the bicycle because of the costs associated with the bicycle frame.
Finally, standard frames have seat tubes which are generally long in the part extending above the top tube of the frame. The storage of the bicycle or its transport, for example in an aircraft, is thus made difficult as a consequence of the space taken up by the frame.